Method for preparing bakery products using mixed partial ester compositions



United States Patent 3,034,897 METHOD FOR PREPARING BAKERY PRODUCTSUSING MIXED PARTIAL ESTER COMPOSITIONS Noel H. Kuhrt and Russell A.Broxholm, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochestel, N.Y., a corporationof New Jersey No Drawing. Filed Dec. 9, 1960, Ser. No. 74,767 22 Claims.(CI. 99-91) This invention relates to the preparation of bakeryproducts, and more particularly, to the preparation of bakery productswith monoglyceride-containing compositions.

It is an object of this invention to provide novel baking processes.

It is another object of this invention to prepare baked products withnovel partial ester compositions containing monoglycerides.

It is another object of this invention to prepare baked products withnew aqueous dispersions of monoglycerides.

It is another object of this invention to prepare baked products withnew aqueous dispersions containing monoglycerides inhibited againstmold.

It is another object of this invention to prepare bread products withnovel partial ester compositions.

It is still another object of this invention to prepare foam-type cakeswith novel partial ester compositions.

It is likewise another object of this invention to pre paretriglyceride-containing cakes with novel partial ester compositions.

Other objects of the invention will be apparent from the description andclaims which follow.

The present invention concerns the preparation of bakery products withpartial ester compositions comprising mixtures of fatty acid monoestersof glycerol and fatty acid monoesters of 1,2-propanediol wherein asubstantial portion of the fatty acid monoesters of glycerol are in anormally unstable polymorphic crystalline form.

The partial ester compositions used in the baking processes of theinvention are comprised predominately of fatty acid monoesters ofglycerol and fatty acid mono esters of 1,2-propanediol. The subjectpartial ester compositions contain 35 to 60 mole percent of monoestersof glycerol and 40 to 65 mole percent of the monoesters of1,2-propanediol, with substantially equal mole proportions beingpreferred.

The fatty acid moieties of the partial esters used in the present bakingprocesses consist essentially of saturated fatty acid moieties having 16to 20 carbon atoms, and include palmitoyl, stearoyl and arachidonylradicals. Partial esters consisting essentially of palmitoyl andstearoyl moieties are preferred. At least 75, and preferably 90, molepercent of the fatty acid moieties of the -monoesters of glycerol arethe same as the fatty acid moieties of the monoesters of 1,2-propanediolin the present partial ester compositions. The fatty acid moieties ofthe present partial esters can be those of hydrogenated fats and oils.The fatty acid moieties of many wellknown fatty materials consistessentially of mixtures of palmitoyl and stearoyl radicals, or suchfatty acid moieties as palmitoyleoyl, oleoyl, linoleoyl, and linolenoylradicals which can be converted by hydrogenation into palmitoyl orstearoyl radicals or mixtures thereof. Fatty acid moieties derived fromsuch hydrogenated fats and oils as lard, soybean oil, cottonseed oil,peanut oil, palm oil, olive oil, beef tallow and others can comprise thefatty acid portion of the partial esters of the invention.

Substantial proportions of the partial esters of glycerol in the presentcompositions are in a thermodynamically normally unstable alpha (a)polymorphic crystalline form. The partial esters of 1,2-propanediol inthe present compositions change from the alpha polymorphic form to thebeta prime (/8') polymorphic form, and in which form they exhibitsubstantial stability. The poly morphic crystalline form of the presentpartial esters can be determined from X-ray diffraction patterns ortracings and infrared curves thereof. The partial esters of glycerol inthe present compositions retain the alpha polymorphic crystalline formfor extended periods of time and have considerable utility in preparingbakery products.

The present partial ester compositions are rapidly solidifying orcrystallizing from the molten state the above-described mixtures offatty acid monoesters of glycerol and 1,2-propanediol. A rapidsolidification of the partial esters is used so that a substantiallyconcurrent solidification or crystallization of the monoester ofglycerol and the monoester of 1,2-propanediol is effected. Suitablerapid solidification methods include the wellknown spray-chillingmethods wherein powdered or bead-' ed products, usually having meshsizes smaller than about 20 and generally smaller than 100, result. Thepartial ester compositions of the invention can also be prepared bysolidifying melts thereof in warm water as described below. The presentmixtures of partial esters are close associations of two crystallinecompounds, namely, the crystals of the partial esters of glycerol andthe crystals of the partial esters of 1,2-propanediol. We have coinedthe name conjoined crystals for the pres ent crystalline partial estermixtures.

The partial ester compositions of the invention have substantial alphacrystal stability. The presence of substantial amounts of unsaturatedfatty acid esters reduces such alpha crystal stability. The fatty acidmoieties comprising the present partial ester compositions generally arecomposed of less than 5 mole percent of unsaturated fatty acid moieties,and preferably consist essentially of saturated fatty acid moieties. Thepresent partial ester compositions thus have low iodine values.Similarly, alpha crystal stability is reduced if the fatty acid moietiesof the glycerol partial ester and the fatty acid moieties of the1,2-propanediol partial ester are substantially different. The partialester compositions of the invention desirably have at least 75, andpreferably 90, mole percent of the same fatty acid moieties on each ofthe partial: esters of the present compositions as described above.

To further illustrate the specificity of the components comprising thepresent partial ester compositions, substitution of closely relatedethylene glycol, 1,3-propanediol or 2,3-butanediol for the1,2-propanediol in preparing the fatty acid partial ester of1,2-propanediol component of the invention, results in a product havinga substantially more rapid alpha to beta crystal shift than the presentpartial ester compositions and are not as useful in the present bakingprocesses.

Aqueous dispersions of the present partial ester compositions have evenfurther extended alpha crystal stability. Generally such aqueousdispersions are prepared to contain about 30% to and preferably about45% to 60%, by weight of water based on the dispersion to formdispersions having a paste-like consistency, although the amount ofwater used can be widely varied. Such aqueous dispersions can beprepared by dispersing in water prepared by the present partial estercompositions in powder form, or by dispersing a molten mixture of thepresent partial ester compositions directly in water. By the lattermethod, the water is desirably first warmed to a temperature of fromabout 30 C. up to the melting point of the partial ester composition.The resulting aqueous dispersion can then be allowed to cool to roomtemperature.

Sorbic acid is preferably added as a mold inhibitor to aqueousdispersions of the present conjoined crystals. We have found that sorbicacid not only functions as a mold inhibitor but also serves to impartimproved properties to the compositions of the invention not imparted byother common mold inhibitors such as sodium propionate. For example,foam-type cakes such as sponge cakes have improved volume and grain whenbaked with the present conjoined crystal compositions of the inventioncontaining sorbic acid. Sorbic acid is particularly useful when cationicmatter such as residual catalyst materials are present in the presentpartial ester compositions. The sorbic acid is suitably employed inconcentrations of 01% to .5% by weight based on the baking mix. Inaddition to sorbic acid and sodium propionate, other well-known moldinhibitors can be utilized in the partial ester compositions of theinvention including propionic acid, lactic acid, 'benzoic acid, butyricacid, and sodium, potassium and calcium salts thereof, as well as sodiumdiacetate and others.

The fatty acid partial esters of glycerol and 1,2-propanediol can beprepared separately and then admixed to prepare the present mixtures ofthe invention. Likewise, such mixtures can be prepared byinteresterifying a triglyceride halving suitable fatty acid moieties, orfree fatty acids, with glycerol and 1,2-propanediol and thereafterseparating out a suitable partial ester composition.

The monoglyceride portion of the present partial ester composition canbe prepared by reacting a suitable triglyceride such as tristearin, or asuitable fatty acid such as stearic acid, or a fatty acid ester of alower monohydric alcohol such as methyl stearate, with glycerine in thepresence of an alcoholysis catalyst, and thereafter separating apurified and concentrated monoglyceride portion by thin film, highvacuum distillation, or by any other suitable separating technique. Thepreparation of high purity monoglycerides by thin film, high vacuumdistillation is described in United States Patents 2,634,234, 2,634,278and 2,634,279. By substituting 1,2-propanedio-l for the glycerol in thereaction with the fatty acid, the monoesters of l,2-propanediol used inthe invention can be similarly prepared, camphorsulfonic acids beingparticularly effective catalysts. The partial esters employed inpreparing the present conjoined crystals are preferably high puritymaterials being at least about 90% monoester such as are prepared bythin film high vacuum distillation, mixtures of monoand diesters showinga more relatively rapid alpha to beta crystal shift.

In accordance with usual practice, we prefer to utilize antioxidants orstabilizers in our conjoined crystal compositions, including suchantioxidants as 2,6-ditertiary 'butyl-4-methylphenol butylated hydroxyanisole and mixtures thereof, tocopherol, and other well-knownantioxidants for fats or oleaginous materials. Mixtures of glycine andphosphoric acid, such as are described in United States Patent2,701,769, are particularly effective.

The present partial ester compositions have considerable utility in thebaking art, the present compositions being substantially more efiectivein preparing bakery products than conventional monoglycerides in thebeta crystalline polymorphic form. Bread prepared with the presentpartial ester compositions has extended shelf-life. Likewise, cakes haveimproved texture, volume and grain or porosity when prepared with thepartial esters of the invention. In addition, the partial ester of1,2-propanediol in the present partial ester compositions is a goodemulsifier and supplements the monoglyceride portion of the presentconjoined crystals. The present partial ester compositions are fullyedible and wholesome and contribute nutritionally to foods to which theyare added.

Only minor proportions of the present conjoined crystal compositions areadded to the baking mix in the present baking processes, withconcentrations of .l% to 3% being suitable and .l% to 1.5% being moregenerally utilized, the concentrations of additive being based on theweight of the baking mix. Concentrations of the present conjoinedcrystal composition additives up to about 10%, and generally about 1% to10%, by weight of the triglyceride fat or shortening are used inpreparing bread and triglyceride-containing cakes such as the well-knownyellow cakes and white cakes. Higher concentrations of the presentadditive may be desired in preparing canned bread. Foam-type cakes suchas the well-known sponge cakes and related cakes containing notriglyceride fat or shortening are generally baked with about .05 to .5%by weight of the flour of the present conjoined crystal compositions.

The term baking mix as used herein refers to the mixture of ingredientsor formula employed in the preparation of the bakery product, and mayinclude such ingredients as flour, shortening, sugar, salt, milk, water,yeast food, yeast, baking powder, emulsifier and the like.

The term bread as used herein refers to the baked product and includesnot only loaf bread, but also, rolls, buns and the like. Likewise, theinvention includes the preparation of various types of breads such aswhite bread, rye bread, whole wheat bread and other well-known types ofbread. The bread can be prepared by any of the wellknown methods,including the sponge and dough procedure, as well as the straight doughmethod.

The invention is further illustrated by the following examples ofpreferred embodiments thereof. Examples 1 to 27 illustrate thepreparation of several conjoined crystal compositions used in the bakingprocesses of the invention and related compositions, and Examples 28 to35 illustrate typical baking processes of the invention.

EXAMPLE 1 One thousand one hundred and sixty grams of fully hydrogenatedlard flakes, 244 grams of glycerol and 304 grams of 1,2-propanediol and1.7 grams of strontium hydroxide were reacted for two hours at 250 C.The reaction product was distilled in a molecular centrifugal still. Theexcess 1,2-propanediol and glycerol were removed by stripping and amixed 1,2-propanediol monoester-glycerol monoester was distilled betweenand 130 C. and at a pressure of 20 The distillate, amounting to 35% ofthe reaction product, had a composition of 0.43 mole of glycerolmonoester and 0.57 mole of l,2propanediol monoester. Three hundred andtwelve grams of this distillate and .02% glycine in a 4% glycerolsolution and .02% phosphoric acid in a 33% glycerol solution were heatedto 85 C. and spray chilled through a spray head of the type used tospray paint (De Vilbiss spray gun) into an open-head container at roomtemperature to produce a finely powdered, free-flowing product having amesh size smaller than mesh. Only 4% of the glycerol monoester in thefinely powdered product was in the beta crystal form with the remainderin the alpha crystal as determined by infrared analysis. The finelypowdered product was readily dispersible in room temperature water.

EXAMPLE 2 Methyl stearate was prepared and fractionally distilled toobtain pure methyl stearate. A purified glycerol monostearate wasprepared in the following manner: 575 grams of methyl stearate, 236grams of GP. glycerol, and 0.8 gram strontium hydroxide were heated at250 C. for 4 hours under nitrogen. Excess glycerol was removed and thereaction product distilled in a molecular centrifugal still at atemperature of l40 C. at 10 pressure. The distilled product analyzed 88%l-monoglyceride which was further purified to 99% l-monoester byrecrystallization from five volumes of 95% petroleum ether boiling 3060C. (Skellysolve F) and ethyl alco- 1101 at room temperature. Asubstantially pure 1,2- propanediol monostearate was prepared in thefollow ing manner: The purified methyl stearate was saponified andacidified to yield pure stearic acid. Then 258 grams of the stearicacid, 206 grams of pure 1,2-propanediol and 0.5 gram of calcium oxidewere heated at 175 C. for hours under nitrogen. A solution of thereaction product in diethyl ether was water washed to remove free1,2-propanediol. The ether-free, washed product was distilled in amolecular centrifugal still at a temperature of 102 C. at 11 pressure togive a 75% yield of substantially pure (99.6%) 1,2-propanediolmonostearate. Thereafter 195 grams of the 1,2-p-ropanediol monostearateand 204 grams of the glycerol monostearate (1:1 mole ratio) were heatedto 80 C. and spray chilled into powder form as described in Example 1.The finely powdered product had a melting point of 6162.5 C. and 14% ofthe glycerol monostearate was in the beta crystal form with theremainder in the alpha form as determined by infrared analysis. Aftertwo months storage at room temperature, the melting point of thepowdered product had not changed, indicating no change in the alpha formof the glycerol monostearate. After storage for 24 months at roomtemperature, the beta crystal form of the glycerol monostearate hadincreased to only 30%. The beta crystal form of the glycerolmonostearate was determined by infrared analysis. The spray chilledpowder when freshly made and after two years storage at room temperaturewas readily 'dispersible in water at room temperature. Powder preparedby spray chilling the glycerol monostearate alone is substantiallycompletely converted to the beta crystal form in less than about 24hours.

EXAMPLE 3 Monoesters of 1,2-propanediol were prepared by reacting 882grams of hydrogenated soy flakes (I.V.=1), 182 grams of 1,2-propanedioland 1 gram of strontium hydroxide at a reflux temperature of 187 C. to220 C. for 3 hours. Excess 1,2-propanediol was removed by water washinga diethyl ether solution of the product. About 960 grams of washedproduct were obtained analyzing for 16% l-monoglyceride (from theglycerol of the fat). The washed product was distilled in a molecularcentrifugal still at a temperature of 108 C. and 14,11 pressure. Thedistillate fraction analyzed 8% l-monoglycer ide and 92% 1,2-propanediolmonoester. A blend was made of 279.4 grams of the above product and228.6 grams of a commercial distilled monoglyceride having the fattyacid moieties of hydrogenated soybean oil and a monoester content ofabout 95%. This mixture of partial esters comprised 48 mole percentglycerol monoester, 51 mole percent propylene glycol monoester, and 1mole percent glycerol diesters. The stabilizer, .02% glycine in a 4%glycerol solution and .02% phosphoric acid in a 33% glycerol solution,was added to the partial ester blend. The blend was heated to 90 C. andspray chilled [into powder form as described in Example 1. The resultingfinely powdered product had a melting point of 555-605 C. and 6% of theglycerol monoester was in the beta crystal form, the remainder in thealpha crystal form as determined by infrared analysis. The beta crystalform of the glycerol monoester after storage at room temperature for sixmonths was 11%, for twelve months was 25% and for eighteen months was26%. The spray chilled powder when freshly made and after eighteenmonths storage at room temperature was readily dispersible in water atroom temperature.

EXAMPLE 4 Monoesters of 1,2-propanediol were prepared by reacting 555grams of a commercial stearic acid (Hystrene S97, containing 90% stearicacid and 10% palmitic acid), 445 grams of 1,2-propanediol and 1 gram ofcalcium oxide at 173 C. for 16 hours. Eight hundred grams of thereaction product were charged to a centrifugal molecular still.Unreacted 1,2-propanediol was removed at a 1 mm. pressure. A high vacuumof 9,11. was obtained and the 1,2-propanediol monoester distilled at 92C. A blend was made of 195 grams of the above product and 195 grams of acommercial distilled monoglyceride hav ing the fatty acid moieties ofhydrogenated soybean oil and a monoester content of about 95 Thismixture of partial esters comprised 48 mole percent of glycerolmonoester and 52 mole percent of 1,2-pr-opanediol monoester. Thestabilizer, .02% glycine in a 4% glycerol solution and .02% phosphoricacid in a 33% glycerol solution was added to the partial ester blend.The blend was heated to C. and spray chilled into finely divided powderas described in Example 1. The finely powdered product had a meltingpoint of 58-60.5 C. and 4% of the glycerol monoester was in the betacrystal form with the remainder in the alpha crystal form as determinedby infrared analysis. The beta crystal form of the glycerol monoesterafter storage at room temperature for six months was 20%, for twelvemonths was 26% and for eighteen months was 27%. The spray chilled powderwhen freshly made and after eighteen months storage at room temperaturewas readily dispersible in room temperature water.

EXAMPLE 5 Monoesters of 1,2-propanediol were prepared by reacting 500grams of a commercial stearic acid (Hystrene S-97, containing stearicacid and 10% palmitic acid), 402 grams of 1,2-propanediol (2 moleexcess) and 0.5 gram of p-toluene sulfonic acid at 120 C. for 5 hours. A819 gram. portion of the resulting reaction product was dissolved in 5parts of diethyl ether and water-washed to remove excess 1,2-propanedio1and catalyst, dried and recovered free of solvent. The washed productanalyzed 83% 1,2-propanediol monoester. This washed product was thendistilled in a centrifugal molecular still at C. to 105 C. at 6 Thepurity of the distilled product was 90.3% 1,2-propanediol monoester and9.7% 1,2-propandio1 diester. A blend of grams of the distilled1,2-propanediol ester product and 100 grams of a commercialmonodiglyceride mixture of saturate fatty acids (Atmul 124, containing58.5% 1- monoglycerides) were prepared. The partial ester blendcomprised 32.8 mole percent l-monoglycerides, 1.2 mole percentZ-monoglycerides, 11.9 mole percent diglycerides, 51.0 mole percent1,2-propanedio1 monostearate and 3.1 mole percent 1,2- propanedioldistearate. The stabilizer, .02% glycine in a 4% glycerol solution and.02% phosphoric acid in a 33% glycerol solution, was added to thepartial ester blend. The blend was heated to 80 C. and spray chilledinto a finely powdered product as described in Example 1. The finelypowdered product had a melting point of 52-55.5 C. and 7% of theglycerol monoester was in the beta crystal form with the remainder inthe alpha crystal form as determined by infrared analysis. The betacrystal form of the glycerol monoester after storage at room temperaturefor 6 months was 14% and for 8 months was 27%.

In Tables Ia and lb below are summarized the results of the alphacrystal stability of several conjoined crystal compositions of theinvention and several other closely related compositions. The variouspartial ester compositions were high purity compositions prepared byhigh vacuum, molecular distillation and then sprayed into powder asdescribed in Example 1 above. The percent beta crystal content set outin Table lb was determined from infrared curves of the variouscompositions. The compositions of the various partial ester compositionsare set out in Table Ia, and the alpha crystal stabilities of thevarious partial ester compositions are set out in Table 1b.

Table Ia COMPOSITION, MOLE PERCENT Glycerol esters Glycol esters 1Example Fatty acid moiety Fatty acid moiety Mono- Dlester Mono- Diesterester ester Stearoyl 49. 2 0. 5 O. 1 7 Hydrogenated lard 43. 5 1.0 2. 08 Hydrogenated soybean oil- 47. 1 l. 2 0

do 38.2 1.4 4. 6 45. 8 1.8 2.0 47. 8 1. 8 l. 3

1 In examples 6 to 10 the glycol was 1,2-propanediol and in Example 11the glycol was 1,3-propanedlol.

Table lb PERCENT BETA CRYSTAL CONTENT OF GLYCEROL MONOESTER [Roomtemperature storage in months] As can be observed from the datasummarized in Tables Ia and 1b, the conjoined crystal compositions ofthe invention as illustrated by Examples 6, 7, 8 and 9, have arelatively slow conversion rate to the beta crystalline polymorphicform. Example 10 illustrates the increased rate of conversion of alphato beta crystalline form when the fatty acid moiety on the glycerolpartial ester is not substantially the same as that on the 1,2-propanediol partial ester. Example 11 points up the specificity of the1,2-propanediol partial esters in preparing the present conjoinedcrystal compositions, the closely related 1,3-propanediol partial estersnot being as effective in retarding the normal alpha to beta crystalshift. If the monoglycerides described in Examples 6 to 11 were preparedand sprayed into powder form from melts thereof in the absence of the1,2-propanediol partial esters, such monoglycerides would besubstantially completely in the beta crystalline polymorphic form withinabout 24 hours. The conjoined crystal compositions of the inventionretain the alpha crystalline polymorphic form for months as describedabove.

The partial ester compositions of the invention are prepared fromsaturated fatty acids, the presence of unsaturated fatty acid moietiessubstantially increasing the alpha to beta crystal shift on storage.Several high purity partial ester compositions having various iodinevalues were prepared by high vacuum molecular distillation and thenspray chilled into powder as described in Example 1. The alpha crystalstability of the various compositions is summarized by the data set outin Table II below. Glycerol and 1,2-propanediol monoesters with variousiodine values were prepared from mixtures of fatty acids similar tothose present in a partially hydrogenated soybean oil. For glycerol and1,2-propanediol monoesters with lower iodine values, the partial esterswere diluted with partial esters prepared from fully hydrogenatedsoybean oil or 1,2-propanediol monostearate. In addition, the variouspartial ester compositions were tested for alpha crystal stability whendispersed in water at a concentration of 40% by weight based on theaqueous dispersion. Those compositions that were tested as aqueousdispersions are indicated as (aqueous) in Table II. The percent betacrystal content set out in Table II was determined from infrared curvesof the various compositions.

BREAD FORMULA sponge aar Flour 65 Mix time: 4% minutes. Water 40. 5Ferment time: 4% hours at 87 F. and

1 75 80% humidity.

35 Mix time: 9% minutes.

27 Floor time: 30 minutes.

6 Proof time: 1 hour, 5 minutes at 98 F.

and 95% humid1ty. Salt 2. 25 Bake time: 20 minutes at 450 F. Milk powder4 Lard 2.0

The Baker Compressimeter employed totest the bread was of the typedescribed in Cereal Laboratory Methods, fifth edition, 1947, compiledand published by the American Association of Cereal Chemists, pages162-165.

EXAMPLE 28 (A) A commercial high purity distilled monoglyceridccomposition having the fatty acid moieties of hydrogenated soybean oiland a monester content of about 95% was heated to 90 C. and spraychilled into powder form as described in Example 1. The resulting finelypowdered product was in the beta crystal form as determined by infraredanalysis after 24 hours storage at room temperature. The monoglyceridepowder was then added at the dough stage in the above described 2% lardbread formula at a level of 4 ounces per 100 lbs. of flour. The breadwas baked with this formulation, with and without the addedmonoglyceride. Sample pieces of the bread were then tested for thesoftness characteristic of fresh bread with a Baker Compressimetcr aftervarying storage times. The results of the test are summarized in Table111 set out below.

(B) A purified 1,2-propanediol monostearate was prepared in thefollowing manner:

Purified methyl stearate was saponified and acidified to yield purestearic acid. Then 400 grams of the prepared stearic acid, 321 grams of1,2-propanediol and .5 gram of calmium hydroxide were heated at 185 C.for 9 hours under an atmosphere of nitrogen. The resulting reactionproduct Was distilled in a molecular still and a fraction taken at 105115 C. at 9a of pressure to give a product analyzing 90.4% monoester and9.6% diester. The desulting 1,2-propanediod monostearate composition wasthen heated to 70 C. and spray chilled into powder form as described inExample 1. The finely powdered product had a melting point of 43.5 -45.8C. and was in the alpha crystal form as determined by infrared analysis.No detectable crystal change occurred for 5 months of storage at roomtemperature. The prepared 1,2-propanediol monostearate powder in thealpha crystalline form was then added to the sponge at the dough stagein the 2% lard bread formula set out above at a level of 4 ounces per100 lbs. of flour. Bread was baked using the 1,2-propanediolmonostearate as the emulsifier and was tested for firmness retardation,with a Baker Compressimeter. The results are summarized by the data setout in Table III below.

(C) A high purity glycerol monostearate was prepared in the followingmanner:

A 575 gram portion of methyl stearate, a 236 gram portion of glyceroland a .8 gram portion of strontium hydroxide were heated at 250 C. for 4hours under nitrogen. Unreacted glycerol was distilled off the reactionproduct and then a fraction taken at 130-140 C. at 10,41. of pressure ona molecular centrifugal still. The distilled product analyzed 88%monoglyceride which was further purified to 99% monoglyceride byrecrystallization from 5 volumes of solvent consisting of 95 petroleumether (boiling 3060 C.) and 5% ethyl alcohol at room temperature. A 204gram portion of the prepared glycerol monostearate and a 195 gramportion of the 1,2-propanediol monostearate prepared as described inExample 28B above 1:1 mole ratio) were combined and heated to C. andspray chilled into powder form as described in Example 1. The resultingfinely powdered product had a melting point of 61-62.5 C., andapproximately 14% of the glycerol monostearate being in the beta crystalform with the remainder in the alpha crystal form as determined byinfrared analysis. After 2 months, storage at room temperature themelting point of the resulting powder product had not changed,indicating no change in the alpha crystal form of the glycerolmonostearate. The finely powdered product was then added as a powder atthe dough stage in the 2% lard bread formula set out above at a level of4 ounces per 100 lbs. of flour. The bread was baked and stored and thentested with a Baker Compressimeter as described in Example 28A above.The results of the test are summarized by the data set out in Table IIIbelow.

Table III Baker compressimeter databread aged 1 in hours Wrapped in waxpaper and stored at 72 F. and 60% relative humidity.

A firmness unit of more than 7 to 8 is indicative of bread having thefirmness characteristic of stale bread. It should be noted that thebread baked with the conjoined crystal composition of the inventionretained a softness characteristic of fresh bread substantially longerthan the bread baked with the monoester of glycerol or the monoester of1,2-propanediol.

EXAMPLE 29 Monesters of 1,2-propanediol were prepared by reacting 1500grams of a commercial stearic acid (Hystrene S- 97," containing stearicacid and 10% palmitic acid), 500 grams of 1,2-propanediol and 4 grams ofd-lO camphorsulfonic acid at 165 C. for 1.5 hours. The reaction productwas charged to a centrifugal molecular still and unreacted glycerolremoved at a pressure of 1 mm. and at a temperature of 85 C. Thereaftera high purity monoester of 1,2-propanediol was distilled over at atemperature of 105 C. and at a pressure of 10p. A blend of 98 grams ofthe resulting monoester and 93.5 grams of a commercial distilledmonoglyceride having the fatty acid moieties of hydrogenated soybean oiland a monoester content of about was heated to 85 C. and spray chilledinto powder form as described in Example 1. The resulting finelypowdered product had a melting point of 56-57.5 C. and about 3% of theglycerol monoester was in the beta crystal form with the remainder inthe alpha crystal form as determined by infrared analysis.

11 The finely powdered monoester mixture was then added as a powder tothe sponge in the dough stage in the bread formula set out above atvarious levels and baked into bread of the 2% lard formula set outabove. The bread was tested for retention of softness characteristic offresh bread with a Baker Compressimeter. The results of the varioustests are summarized by the data set out in Table IV below. The amountof monoglyceride additive in Table IV below is set out in terms ofounces of additive per 100 lbs. of flour in the bread formula.

Table IV Baker compressimeter databread aged 1 in hours Emulsifieradditive None 4.6 6.4 7.8 9.2 9.4 12.0 3.5 oz. mixture of glycerolmonoester and 1,2-propanediol monoester 3.4 3.6 5.9 5.2 6.8 8.2 2.84 oz.mixture of glycerol monoester and 1,2-propancdiolmonoester 3.8 4.0 5.05.4 7.0 8.0 2.13 oz. mixture of glycerol monoester and1,2-propanediolmonoester 3.2 4.0 5.2 7.2 8.2 9.4 1.42 oz. mixture ofglycerol monoester and 1,2-propanediolnionoester 3.6 4.6 5.0 7.0 8.6 9.20.71 oz. mixture of glycerol monoester and 1,2-propanediolmonoester 3.84.6 6.6 8.8 10.4 11.6

Wrapped in wax paper and stored at 72 F. and 60% relative humidity.

EXAMPLE 30 A blend of 98 grams of the 1,2-propanediol monoester and 93.5grams of a commercial distilled monoglyceride produce containing thefatty acid moieties of hydrogenated soybean oil and comprising about 95%monoester as described in Example 29 was heated to 85 C. and spraychilled into powder form as described in Example 1. A dispersion wasprepared with 2 parts by weight of the freshly spray chilled powder and3 parts by weight of water at room temperature and were blended to forma smooth paste. This paste was then added at levels of 8.9 ounces, 7.1ounces, 5.3 ounces and 3.5 ounces per 100 lbs. of flour directly to thesponge of the 2% lard bread formula set out above. Bread was preparedwith and without the subject emulsifier. The cell structure of the breadbaked with the emulsifiers was excellent and exceedingly close grainedand exceptionally white in color. The bread was stored at varyinglengths of time and tested for retention of softness characteristic offresh bread with a Baker Compressimeter. The results of the test aresummarized by the data set out in Table V below.

! Wrapped in wax paper and stored at 72 F. and 60% relative humidity.

EXAMPLE 31 Bread prepared with the 2% lard formula described above wasprepared with 7 ounce portions per 100 lbs.

of flour of the glycerol monoester and 1,2-propanediol monoesterconjoined crystal mixture in the aqueous dispersion described in Example30 that was freshly prepared and also with a similar dispersion that was2 years old. Similar compartive bread samples were prepared with 7ounces per 100 lbs. of flour of aqueous dispersions of a distilledglycerol monoester having the fatty acid moieties of hydrogenated lardand a monoester content of at least that was fresh and also that was 28days old. The bread was baked and thereafter tested with a BakerComprcssimeter for retention of softness characteristic of fresh bread.The data is summarized in Table VI below.

1 Wrapped in wax paper and stored at 72 F. and 60% relativehumidity Ascan be observed from the data in Table VI, that while freshly preparedglycerol monoester is effective in retarding firmness in bread, thisproperty deteriorates on standing a relatively short period of time.However, the conjoined crystal composition of the invention retaineddesirable properties for 2 years.

The partial ester compositions of the invention have considerableutility in triglyceride cake mixes as emulsifiers in a dried powderform. We have found that the present partial ester compositions can beincorporated with the other dry ingredients of presently prepared cakemixes and need not be incorporated in the shortening. in Examples 32 and33 below the cakes were prepared with the following formula \VHITE CAKEMIX FORMULA Ingredients: Parts by weight Flour 41.5 Sugar, granulated43.5 Powdered egg white 1.8 Salt 1.2 Baking powder 2.5 Hydrogenatedvegetable oil 9.5

In baking with the above cake formula, 60% by weight of whole milk basedon the formula is used. One of the improved features of the partialester compositions or conjoined crystal compositions of the inventionwhen used as emulsifiers in cake mixes is the ability of such mixes tohold and retain air incorporated in the mixing step as well as the gasreleased by the baking powder. So substantial an amount of air can beincorporated by mixing cake mixes containing the present partial estercompositions that new types of baking powder which release their carbondioxide only with heat, or a slower acting baking powder necessary ifthe batter is to stand before being baked, or if the batter isrefrigerated, can be utilized. Likewise, if a cake mix is desired whichwill not require much mixing to incorporate air but can utilize fullythe production of carbon dioxide from the baking powder, the presentpartial ester compositions are very useful. Cakes prepared with thepresent partial ester compositions A 98 gram portion of distilled1,2-propanediol monostearate prepared as described in Example 4 wasblended with a 93.5 gram portion of a commercial distilled monoglyceridehaving the fatty acid moieties of hydrogenated soybean oil and amonoglyceride content of about 95% were heated to 85 C. and spraychilled into powder form as described in Example 1. The finely powderedproduct had a melting point of 5657.5 C., with 3% of the glycerolmonoester being in the beta crystal form and the remainder being in thealpha crystal form as determined by infrared analysis. The powderedpartial ester mixture was then added to the above cake mix formula atlevels of 1% to 4% based on the hydrogenated vegetable oil shortening.Similarly, 1% to 4% portions based on the weight of the hydrogenatedvegetable oil shortening of a commercial distilled monoglyceride havingthe fatty acid moieties of lard and a monoester content of about 95%were incorporated in other samples of the above baking mix. The cakeswere then baked in 8 inch layer cake tins, approximately 380 grams ofbatter in each cake tin for 21 minutes at 350 F. Table VII belowsummarizes the density and appearance of the batters of the cakesprepared with the various emulsifiers as well as the porosity of thebaked cakes. The values indicating porosity in the tables are based on:1 being average porosity, 1+ being improved porosity, 1+;+ being stillfurther improved porosity and l being less than average porosity. In thetables referring to the appearance of cake batters, the term S1. curd.,sl. thick refers to a batter that is slightly curdled and slightlythickened, the term V. sl. curd. refers to a batter that is veryslightly curdled, etc.

It is observed from the data and information summarized in Table VIIthat the conjoined crystal compositions of the invention produce cakebatters having lower density and improved cake porosity as compared toconventional monoglycerde compositions.

EXAMPLE 33 The conjoined crystal composition of the invention preparedas described in Example 32 was incorporated at a by weight level basedon the hydrogenated vegetable oil shortening in the above cake mix andstored at room temperature for periods up to three months. Cakes werebaked periodically with the partial ester mixturecontaining mix and wereevaluated for batter density and appearance and baked cake porosity andvolume. The cake was baked as described in Example 32. During the threemonth period the cake mixes showed good batter density indicating a goodretention of air and gas, and an improvement in cake texture and volume.The results of the baking tests are summarized in Table VIII below.

Table VIII Batter Baked Cake Dry cake mix storage time Volume,

Density Appearance Porosity M1./lb.

batter 0 days 0.85 V. sl. curd., g00d 1++ 1,290 1 week 0.81 do 1++ 1,300 4 weeks. 0. S5 1++ 1, 300 7 weeks. 0.85 1++ 1, 335 12 weeks 0. 811++ 1, 305

The partial ester compositions of the invention have utility infoam-type cakes. Foam-type cakes do not contain triglyceride shorteningsand when conventional monoglycerides are utilized as emulsified in theirpreparation they tend to break the emulsion formed by the eggs andresult in poor cakes. Foam-type cakes are so-called because the body ofthe cake batter as well as the major supporting framework of the bakedcake depends on the aeration or beating of the eggs into a foam-likemass. A commonly used emulsifier for foam-type cakes is an aqueousdispersion of polyoxyethylene partially stearated sorbitol. However,this emulsifier does not contribute a desirable substantial increase involume. We have found that the partial ester compositions of theinvention impart to foam-type cakes when used in their preparation,substantially improved volume as well as improved texture. In Examples34 and 35 below the following foam-type cake formula was utilized.

Sponge cakes were baked with .5% by weight based on the flour in theabove formula of variou emulsifying agent and Were observed with respectto improvement of porosity and volume. A conjoined crystal compositionof the invention prepared as described in Example 3 was dispersed in 3parts by weight of water for each 2 parts by weight of conjoined crystalcomposition and used as the emulsifier in baking the cakes. Similarly,.5% by weight of a similar aqueous dispersion of 1,2-propanediolmonostearate, .5 by Weight of an aqueous dispersion of monoglyceridecontaining the fatty acid moieties of hydrogenated lard and having amonoester content of about and .5% by weight of an aqueous dispersion ofpolyoxyethylene partially stearated sorbitol (Vanlite) were employed asemulsifiers in the baking of a foamtype cake with the above formula. Thepartial ester additives were added at the first stage of the mixing ofthe water, sugar, milk powder and eggs. The ingredients were then mixedwith a wire whip for 5 minutes at high speed. Flour, baking powder andsalt were then added and mixing continued for 2 minutes at low speed.The cakes were baked in 8 inch round layer tins containing 200 grams ofbatter for 17 minutes at 360 F. The

results of the comparative baking tests are summarized in Table IXbelow.

It is to be noted from Table IX that the cake baked with the conjoinedcrystal composition of the invention had good porosity and volume. Thebatter prepared with the conjoined crystal composition of the inventionalso had a desirable low density. All three of these properties were notimparted by the monoglyceride alone, the 1,2- propanediol monoesteralone, or the sorbitol derivative alone.

EXAMPLE 35 We have found that sorbic acid is an effective mold inhibitorfor aqueous dispersions of the present partial ester compositions. Inaddition, sorbic acid imparts to foam-type cake improved grain andtexture as compared to such other commonly used mold inhibitors assodium propionate. A 9.7 gram portion of 1,2-propanediol monostearateand 10.3 grams of a commercial distilled monoglyceride having the fattyacid moieties of hydrogenated lard and a monoester content of about 95%were melted together and added with stirring to ml. of warm watercontaining .05 gram of sorbic acid and a smooth paste was formed. Theresulting paste was then added to the batter of the sponge cake formulaset out above at a level of .5% by weight based on the flour and mixedand baked as described in Example 34. A sponge cake batter was madewithout added emulsifier to serve as control. Similarly, a cake batterwas prepared substituting .05 sodium proporionate for the sorbic acid.The cakes were baked in 8 inch round layer tins containing 200 grams ofbatter for 17 minutes at 360 F. The baked cake containing the sorbicacid had approximately 1.8 times greater volume than the cake containingno emulsifier. from the cake baked with the sodium propionate. How ever,the cake baked with the sorbic acid had good texture while the cakebaked with the sodium propionate had a more open texture.

The conjoined crystal compositions used in the present baking processesare also described in our copending application titled Mixed PartialEster Compositions that was filed concurrently herewith.

Although the invention has been described in detail with particularreference to certain typical embodiments thereof, it will be understoodthat variations and modifications can be effected within the spirit andscope of the invention as described hereinabove and as defined in theappended claims.

We claim:

1. The method for preparing bakery products which comprisesincorporating into the baking mix prior to baking .1% to 3% by weightbased on the baking mix of a partial ester composition comprisedpredominantly of concurrently solidified fatty acid monoester ofglycerol and fatty acid monoesters of 1,2-propanedio1, said partialester composition containing to 60 mole percent of said monoesters ofglycerol and to 65 mole percent of said monoesters of 1,2-propanediol, asubstantial portion of said monoesters of glycerol being in a normallyun- Similar improved volume resulted stable polymorphic form, the fattyacid moieties of said monoesters consisting essentially of saturatedfatty acids having 16 to 20 carbon atoms, at least about 75 mole percentof the fatty acid moieties of said monoesters of glycerol being the sameas the fatty acid moieties of said monoesters of 1,2-propanediol, andless than about 5 mole percent of the fatty acid moieties comprisingsaid partial ester composition being unsaturated fatty acid moieties.

2. The method defined in claim 1 wherein the paitial ester compositionis added to the baking mix in an aqueous dispersion.

3. The method defined in claim 1 wherein the fatty acid moieties of thepartial ester composition are palmitoyl moieties.

4. The method defined in claim 1 wherein the fatty acid moieties of thepartial ester compositions are stearoyl moieties.

5. The method defined in claim 1 wherein the fatty acid moieties of thepartial ester composition are mixtures of palmitoyl and stearoylmoieties.

6. The method defined in claim 1 wherein the fatty acid moieties of thepartial ester composition are selected from the group consisting offatty acid moieties derived from hydrogenated fats and oils consistingessentially of palmitoyl and stearoyl moieties.

7. The method defined in claim 1 wherein the partial ester compositioncontains a minor proportionate amount of sorbic acid.

8. The method for preparing bread which comprises incorporating into thebaking mix prior to baking .l% to 3% by weight based on the baking mixof a partial ester composition comprised predominantly of concurrentlysolidified fatty acid monoesters of glycerol and fatty acid monoestersof 1,2-propanediol, said partial ester composition containing 35 to 60mole percent of said monoesters of glycerol and 40 to mole percent ofsaid monoesters of 1,2-propanediol, said monoesters of glycerol beingpredominantly in the alpha polymorphic crystalline form, the fatty acidmoieties of said monoesters consisting essentially of a fatty acidmoiety selected from the group consisting of palmitoyl moieties, steroylmoieties and mixtures thereof, at least 90 mole percent of the fattyacid moieties of said monoesters of glycerol being the same as the fattyacid moieties of said monoesters of 1,2- propanediol, and the fatty acidmoieties comprising said partial ester composition consistingessentially of saturated fatty acid moieties.

9. The method defined in claim 7 wherein the monoesters of glycerol and1,2-propanediol are used in substantially equal mole proportions.

10. The method defined in claim 7 wherein the fatty acid moieties of thepartial ester composition are those of hydrogenated soybean oil.

11. The method defined in claim 7 wherein the fatty F acid moieties ofthe partial ester composition are those of hydrogenated lard.

12. The method defined in claim 7 wherein the partial ester compositionis added to the baking mix in an aqueous emulsion comprising about 30%to by weight of water based on said emulsion.

13. The method for preparing foam-type cakes which comprisesincorporating into the baking mix prior to baking .1% to 3% by weightbased on the baking mix of a partial ester composition comprisedpredominantly of concurrently solidified fatty acid monoesters ofglycerol and fatty acid monoesters of 1,2-propanediol, said partialester composition containing 35 to 60 mole percent of said monoesters ofglycerol and 40 to 65 mole percent of said monoesters of1,2-propanediol, said monoesters of glycerol being predominantly in thealpha polymorphic crystalline form, the fatty acid moieties of saidmonoesters consisting essentially of a fatty acid moiety selected fromthe group consisting of palmitoyl moieties, stearoyl moieties andmixtures thereof, at least mole percent 17 of the fatty acid moieties ofsaid monoesters of glycerol being the same as the fatty acid moieties ofsaid monoesters of 1,2-propanediol, and the fatty acid moietiescomprising said partial ester composition consisting essentially ofsaturated fatty acid moieties.

14. The method defined in claim 12 wherein the monoesters of glyceroland 1,2-propanediol are used in substantiaily equal mole proportions.

15. The method defined in claim 12 wherein the fatty acid moieties ofthe partial ester composition are those of hydrogenated soybean oil.

16. The method defined in claim 12 wherein the fatty acid moieties ofthe partial ester composition are those of hydrogenated lard.

17. The method defined in claim 12 wherein the partial ester compositionis added to the baking mix in an aqueous emulsion comprising about 30%to 70% by weight of water based on said emulsion.

18. The method for preparing triglyceride-containing cakes whichcomprises incorporating into the baking mix prior to baking .1% to 3% byweight based on the baking mix of an ester composition comprisedpredominantly of concurrently solidified fatty acid monoesters ofglycerol and fatty acid monoesters of 1,2-propanediol, said partialester composition containing 35 to 60 mole percent of said monoesters ofglycerol and 40 to 65 mole percent of said monoesters of1,2-propanediol, said monoesters of glycerol being predominantly in thealpha polymorphic crystalline form, the fatty acid moieties of saidmonoesters consisting essentially of a fatty acid moiety selected fromthe group consisting of palmitoyl moieties, stearoyl moieties andmixtures thereof, at least 90 mole percent of the fatty acid moieties ofsaid monoesters of glycerol being the same as the fatty acid moieties ofsaid monoesters of 1,2-propanediol, and the fatty acid moietiescomprising said partial ester composition consisting essentially ofsaturated fatty acid moieties.

19. The method defined in claim 17 wherein the monoesters of glyceroland 1,2-propanediol are used in substantially equal mole proportions.

20. The method defined in claim 17 wherein the fatty acid moieties ofthe partial ester composition are those of hydrogenated soybean oil.

21. The method defined in claim 17 wherein the fatty acid moieties ofthe partial ester composition are those of hydrogenated lard.

22. The method defined in claim 17 wherein the partial ester compositionis added to the baking mix in an aqueous emulsion comprising about to byweight of water based on said emulsion.

No references cited.

1. THE METHOD FOR PREPARING BAKERY PRODUCTS WHICH COMPRISESINCORPORATING INTO THE BAKING MIX PRIOR TO BAKING .1% TO 3% BY WEIGHTBASED ON THE BAKING MIX OF A PARTIAL ESTER COMPOSITION COMPRISEDPREDOMINANTLY OF CONCURRENTLY SOLIDIFIED FATTY ACID MONOESTERS OFGLYCEROL AND FATTY ACID MONOESTERS OF 1,2-PROPANEDIOL, SAID PARTIALESTER COMPOSITION CONTAINING 35 TO 60 MOLE PERCENT OF SAID MONOESTERS OFGLYCEROL AND 40 TO 65 MOLE PERCENT OF SAID MONOESTER OF 1,2-PROPANEDIOL,A SUBSTANTIAL PORTION OF SAID MONOESTER OF GLYCEROL BEING IN A NORMALLYUNSTABLE POLYMORPHIC FORM, THE FATTY ACID MOIETIES OF SAID MONOESTERSCONSISTING ESSENTIALLY OF SATURATED FATTY ACIDS HAVING 16 TO 20 CARBONATOMS, AT LEAST ABOUT 75 MOLE PERCENT OF THE FATTY ACID MOIETIES OF SAIDMONOESTERS OF GLYCEROL BEING THE SAME AS THE FATTY ACID MOIETIES OF SAIDMONOESTERS OF 1,2-PROPANEDIOL, AND LESS THAN ABOUT 5 MOLE PERCENT OF THEFATTY ACID MOIETIES COMPRISING SAID PARTIAL ESTER COMPOSITION BEINGUNSATURATED FATTY ACID MOIETIES.